1. Field of Use
This invention relates generally to valve apparatus for use in fluid conveying systems. In particular, it relates to valve apparatus which periodically effects rapid opening of a valve to admit air into a vacuumized fluid line in the fluid conveying system.
2. Description of the Prior Art
The dairy industry employs fluid conveying systems wherein milk is conveyed by pipeline from the milking parlor to the milk storage area. Such systems include fluid washing apparatus for the pipelines. Such cleaning-in-place apparatus is shown and described in the U.S. Pat. Nos. 3,119,399 issued Jan. 28, 1964 entitled Apparatus for Washing Milk Conducting Lines by Lloyd F. Bender and 3,191,576 issued June 29, 1965 entitled Milk Line Releaser and Washer Apparatus issued to Lloyd F. Bender. These patents relate to apparatus for automatically moving fluid under a constant and continuous vacuum and even during the periodic fluid dumping operation. They provide apparatus for cleaning a pipeline for milk and the like by subjecting the interior of the link to a succession of relatively short cleansing slugs separated by air-filled spaces and by advancing a series of spaced liguid slugs with a scouring action through the milk line at a rapid rate. Patent 3,119,399 utilized a timer, shown in FIGS. 7, 8 and 9 for periodically connecting the interior of the pipeline with the ambient air of the atmosphere to alternately cut off the air admission and allow the milk line to receive successive liquid slugs from a tank of cleaning solution. This patent used a rotary valve type device but that device had the limitation in that the orifice used to emit air opened and closed slowly as the rotor passed the orifice and for large diameter milk conducting lines that device was not entirely successful. Patent 3,191,576 also used an electrically actuated timer and rotary valve for intermittently admitting successive slugs of cleaning solution separated by atmospheric airfilled spaces and this timer was also of the type shown in the said U.S. Pat. No. 3,119,399.
Other prior art devices relating generally to this type of equipment utilized an electrical solenoid to pull a stopper plug out of an orifice in a fluid line to emit the air. Such devices are shown in the U.S. Pat. Nos. 3,802,447 issued Apr. 9, 1974 for Automatic Tank Washer with Spin-Burst Mechanism for Washing, Rinsing, and Sanitizing of Lloyd F. Bender; 3,670,744 issued June 20, 1972 for Solenoid Operated, Two Way Diverter Valve for Fluid Line Washing Apparatus of Lloyd F. Bender; and 3,732,891 issued May, 15, 1973 for Solenoid Operated, Two Way Diverter Valve for Fluid Line Washing Apparatus of Lloyd F. Bender. The pulling force of the vacuum in the fluid line and against which the solenoid must act to operate or move the stopper plug is very great. Accordingly, it is desirable to provide improved valve apparatus for such systems.